Imitation leather paper



April 1937- H. e. KITTREDGE AL 2,077,112

IMITAT ION LEATHER PAPER Filed Dec. 28, 1954 INVENTORQ //41?V5 K/TTEEDGE9:

flLBEET J. TUE/V512 By W pm 2 Patented A r. 13, 1937 UNITED STATES-PATENT OFFICE IMITATION LEATHER PAPER Delaware Application December 28,1934, Serial No. 759,550

1 Claim.

This invention relates to a new article of manufacture for use asimitation leather having the appearance, feel and body of leather.

It is the object of the invention to provide imitation leather paperwhich has a wrinkled, leather-like surface but which is not embossed,pressed or formed.

It is an object to provide such a leather-like paper, paper board or anyother cellulose material which has such an appearance.

It is a further object to provide such an imitation leather paper thatthe leather finish will be on one side but the other side will remain inits normal condition for ordinary uses of packag- 3 ing, printing, etc.

It is an object to provide a product to which the leather-like surfacecan be applied in any color, which can be applied and dried at ordinarytemperatures of a room from sixty to seventy degrees Fahrenheit, orwhich may be baked as high as two hundred and twenty five degreesFahrenheit; it is a further object to provide such a leather-like paperconsisting of the wrinkled leather-like coating that can be sprayed,dipped,

i impregnated or applied in any manner to the surfaces of the paperwithout the necessity of any intermediate backing, sizing or othertreatment of the paper.

It is anobject to provide such a leather-like finish that will penetratethe surface of the paper sufiiciently to .form an intimate bond with thepaper or other cellulose material to which it is applied but which willnot penetrate the paper itself completely.

It will be understood in this application that when we refer to paper,we refer to any compound of cellulose.

Referring to the drawing:

The figure is a section through a cellulose backing, such as of paper,with theimitation leather finish mounted thereon.

Referring to the drawing in detail, I is a cellulose backing of paper,pasteboard, straw-board, cellophane, or any other cellulose material. 2indicates the zone of penetration forming the bond between the paper Iand the imitation leather finish 3. This finish is corrugated insubstantially regular corrugations indicated at 4.

Upon the application of this finish, depending upon its exactcomposition, the finish will begin to wrinkle and will be completelywrinkled substantially throughout the body of the finish.

Even though the paper or other supporting backing is of very thinmaterial, its wrinkle will 55 not be imparted through the material. The

paper is opaque and the imitation leather finish will not penetratethrough or be seen from the reverse side of the paper.

It is therefore possible to either have the plain paper on the oppositeside from the flnish for printing and the like, or a finish of the sameor diiferent color can be imparted to the supporting medium I.

In applying this imitation leather finish, as hereinafter described, itis essential that the temperature of drying be not carried to a pointwhere the paper will be injured. It is possible with our invention tokeep within the limits of safety for the paper as the finishes which weprovide range from those that dry in the air at room temperatures from60 to 70 degrees Fahrenheit to those that can be baked at from 200 to225 degrees Fahrenheit.

Typical compounds for the production of this new article of manufactureare as follows:

. EXAMPLE 1 In this example we use one of two varnishes,

or a combination of two varnishes with a. drier. These varnishes aredesignated Varnish A" and Varnish B.

Varnish A Amberol is a phenol, formaldehyde, synthetic resin. It is madeas follows: to one hundred parts of phenol aldehyde resin difiicultlyfusible and only partly soluble in benzol and other solvents andproduced, for instance, by heating 108 parts of cresol with 60 to 75parts of formaldehyde by weight) and distilling off the water and theuncombined cresol, are added gradually to 800 parts of melted colophony.The whole mixture is then heated in an autoclave until a resin isproduced which is clear in the cold, homogeneous and free fromsmell ofphenol. The volatile substances are then removed while stirring andIOU-parts of glycerol of 28 degrees B. are added in small quantitieswhereupon the mixture is heated to 250 degrees C. and kept at thistemperature for several hours while being stirred carefully. A typicalformula for amberol is shown in United States Patent No. 1,623,901.

In order to prepare this varnish, we first take 20 gallons of China woodoil or tung oil and 2% gallons refined linseed oil. These oils are mixedand heated at a normal rate to 480 degrees F. They are then pulled fromthe fire. These oils may undergo an automatic rise in temperaturethereafter beyond 480 degrees F., but this is unnecessary and too greata rise should be avoided.

When the temperature of these'oils has started to drop reachingapproximately 475 degrees R, we add 3 /2 pounds of litharge, stirringuntil the litharge is taken up by the oil. The temperature of this batchis then run back and forth between 460 degrees and 4'70 degrees,beingheld within this range for approximately 30 minutes and in somecases a little longer until sumcient body has been imparted tothe oiland litharge.

Thereafter we add 8 pounds of manganese solid linoleate and 2 pounds ofcobalt solid linoleate. These soluble driers melt into the batch.

We then add 6'7 pounds of synthetic resin solid, known to the trade asAmberol B/S 1' Light. This is melted at a low heat. Then the temperatureis carried back to approximately425 degrees F.

We then thin the batch at once with 14 gallons each of heavy and lightpetroleum naphtha.

The resulting compound may be used by itself or in combination with theproduct of the formula hereinafter recited.

Thereafter we prepare Varnish B.

Varnish B This formula is as follows:

The cooking is carried out in this manner. Sixty-seven pounds of I SouthSea gum, also known as Batu gum, are run in the ordinary approvedfashion customary in varnish making. Then 20 gallons of China-wood oiland 2% gallons of refined linseed oil are mixed and heated slowly untilthey reach 300 or 350 degrees F., when' they are added slowly to the gumwhen the latter has been well run.

The mixture is then carried to a. temperature of 460 to 470 degrees F.and held within this range, in order to impart body to the mixture, forabout 30 minutes or a little longer.

We then stir into the batch 3% pounds of litharge until it is taken upand fully incorporated in the batch. The 8 /2 pounds of manganese solidlinoleate and 2 pounds of cobalt solid linoleate are allowed to melt inthe batch. We then thin at once with 20 gallons each of heavy and lightpetroleum naphtha. Turpentine may be substituted for the naphtha.

In order to make the compound of this invention, either one of the abovevarnishes or both are combined with raw tung (China-wood) oil and adrier. A thinner can be added optionally.

Parts Varnish A 81 Varnish B 40 Raw tung (China-wood oil) 9 Drier 9Petroleum naphtha 5-10 To one gallon of this compound we add 5 to 7pounds of the desired color, previously ground in spar varnish.

Varnish A has the function of fast drying, and imparts a high luster.Varnish B has a medium drying rate, and provides a low luster. Chinawoodoil facilitates a very wrinkled drying without gloss and adds opacity tothe product. The thinner controls the viscosity and the drier has thefollowing functions and characteristics.

When the compound of this invention is applied it must first flow outevenly on the surface treated and then the drying must begin almost atonce on the surface of the wet compound by the formation f microscopicwrinkles. This initial wrinkling then proceeds through the wholethickness of the film as the complete drying proceeds.

The preferred drier that we have found to best serve this purposecomprises linoleate of lead, linoleate of cobalt, and linoleate ofmanganese. The cobalt and manganese, particularly the cobalt, acceleratethe surface drying, as described above, while the lead and manganese areutilized for completing the drying completely through the film Thiscombination of cobalt and manganese supplies quick initial surfacedrying necessary, while the lead and the manganese supply the necessarycatalytic action for the drying through the film.

Drier example One of the preferred formulas which we have used is asfollows:

- Pounds Linoleate of lead 385 Linoleate of cobalt 889 Linoleate ofmanganese 14 These are melted at as low heat as possible, and whenentirely fluid the mass is thinned with 1202' gallons of turpentine,either gum spirits or wood spirits, or some slowly evaporating coal tarfraction, such as xylene. It will be understood that the proportions ofthese elements of the drier can be varied according to the resultdesired. By adjusting these proportions the velocity of the surfacedrying and drying throughout the film can be regulated.

- EXAMPLE 2 When it is desired particularly to utilize light colors andpastel shades in the imitation leather finish which may be baked atlower temperature with the minimum of discoloration, the finish of thepresent example is employed provided the temperature is not taken beyondapproximately 225 degrees F. so as not to injure the paper.

In this example there are two varnishes known as Varnish C and VarnishD. Either one or both varnishes may be employed.

Varnish C In order to make the first varnish designated as above, wetake 100 pounds of Amberol 3/8 1 Lt. and 14 gallons of raw China-woodoil, heating the China-wood oil and the above synthetic resin in avarnish kettle to 550 degrees F. Three pounds of linoleate of lead andone pound of linoleate of cobalt are then added and stirred thoroughly.The batch is then allowed to cool to 450 degrees F. and then reducedwith 32 gallons of petroleum naphtha.

Varnish D 30 Varnish C gallons 11% Varnish D do Raw China-wood oil. do1% Thinner composed of equal parts of toluol 35 and petroleum naphthagallons.-- 1-2 Paste composed of pure titanium dioxide ground in a sparvarnish pounds 120 This enamel may be applied in any manner, as byinking rolls or by spray.

40 When the supporting surface, such as the paper sheet, is so treated,it is passed through the varnish at a temperature not to exceedapproximately 250 degrees F. and is held at-that temperature for about 2to 3 hours. These tem- 45 peratures and the time oi baking, the natureof the atmosphere in which baked, and the movement of that atmospherewill depend upon the supporting material. We merely mention typicalexamples.

50 The resulting product will have a wrinkled surface imitating leather,but the paper structure itself will notbe disturbed except that on thesurface to which the product is applied there will be suflicientpenetration to bond the coating to 'the paper. The surface will appearwrinkled and substantially without discoloration irrespective of itsdelicate colors. There will v be provided a smooth, heavy and wrinkledor pebbled surface which is a close imitation of genuine leather.

Varnish C and Varnish D can be varied in proportions of two to one ofVarnish C to Varnish D, ortwo to one of Varnish D with respect toVarnish C. Raw China-wood oil can be varied in the same combination fromone to ten parts. That is, from one to ten gallons, when gallons areused as the measure of the parts. The more China-wood oil used, the lessthe luster, and the finer the finish or grain of the leather.

Difierent colors may: be employed; such as: ultramarine blues; chromeyellows and greens; chromium oxide greens; toluidine and lithol reds,etc.

In the foregoing varnishes the proportions may be varied, but we preferthe proportions indicated, which we have found to be practicalv'arnishesfor this purpose;

By cellulose backing is comprehended a variety of products, such aspaper, pasteboard, cellophane and any others made of cellulose or itsderivatives. Enumeration of these specific articles is not to beconstrued as a limitation or an exclusion of others of similarcharacter.

It will be understood that we desire to comprehend within our inventionsuch modifications as come within the scope of our claims and ourinventioni Having thus fully described our invention, what we claim asnew and desire to secure by Letters Patent, is: I

In a method of making imitation leather which comprises applying to oneside only of flexible cellulose material a composition containing rosinmodified phenol-formaldehyde resin, raw Chinawood oil, cobalt linoleate,lead linoleate, a thinner and a coloring agent, and drying the coatingat a temperature sufiiciently high to form a wrinkled leather-likesurface bonded to the flexible material by a partial penetrationthereof.

the temperature of drying not being carried to a point where theflexible cellulose material will be injured.

HARVEY G. .KI'I'I'REDGE. AIBERTJ. TURNER.

